Going Portable with the Airspy HF+, Raspberry Pi and 7-Inch Touch LCD

Over on the swling blog we've seen a post where contributor 'Tudor' demonstrates his Airspy HF+ running nicely on a Raspberry Pi 3, 7-inch touchscreen LCD, and USB power bank. The video shows GQRX running very smoothly on the Pi, and how the setup is able to receive various HF signals. Tudor writes:

I bought the RPi to use it as a Spyserver for my Airspy HF+ SDR.

My main radio listening location is a small house located on a hill outside the city and there is no power grid there (it’s a radio heaven!), so everything has to run on batteries and consume as little power as possible.

My first tests showed that the Raspberry Pi works very well as a Spyserver: the CPU usage stays below 40% and the power consumption is low enough to allow it to run for several hours on a regular USB power bank. If I add a 4G internet connection there I could leave the Spyserver running and connect to it remotely from home.

Then I wondered if the Raspberry Pi would be powerful enough to run a SDR client app. All I needed was a portable screen so I bought the official 7” touchscreen for the RPi.

I installed Gqrx, which offers support for the Airspy HF+. I’m happy to say it works better than I expected, even though Gqrx wasn’t designed to work on such a small screen. The CPU usage is higher than in Spyserver mode (70-80%) but the performance is good. Using a 13000 mAh power bank I get about 3.5 hours of radio listening.

On the swling blog post comments Tudor explains some of his challenges including finding a battery that could supply enough current, finding a low voltage drop micro-USB cable, and reducing the noise emanating from the Raspberry USB bus. Check out the post comments for his full notes.